quirk

1an aspect of somebody’s personality or behaviour that is a little strangesynonympeculiarityEveryone has their own little quirks and mannerisms.

2a strange thing that happens, especially by accidentBy a strange quirk of fate they had booked into the same hotel.an unpredictable quirk of history

Word Originearly 16th cent. (as a verb): of unknown origin. The early sense of the noun was ‘subtle verbal twist, quibble’, later ‘unexpected twist’.Extra examplesThe system has some odd little quirks.as a result of some quirk in the social orderIt was a remarkable quirk in his otherwise orderly character.Perhaps it’s some quirk in your nature that makes you behave like that.They accepted it as one of her little quirks.